共查询到17条相似文献,搜索用时 110 毫秒
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影响牺牲层腐蚀速率的因素研究 总被引:2,自引:0,他引:2
精确预测腐蚀速率对于避免过腐蚀和节省时间,从而提高MEMS器件加工的效率具重大意义.通过改变牺牲层材料、腐蚀液浓度、温度和牺牲层结构来改变腐蚀速率是常用的方法.在前人腐蚀模型基础上考虑扩散系数是浓度和温度的函数,腐蚀速率常数是温度的函数,得到了修正模型.从修正模型中找出影响腐蚀速率的各种因素的对应参数,并对其影响腐蚀速率的机理进行详细地研究,这样就为通过修改某些因素来改变腐蚀速率提供了依据. 相似文献
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通过大量的实验研究,建立了一套纳米量级牺牲层腐蚀行为的实验研究方法.对牺牲层厚度对腐蚀速率的影响进行了详细地研究,并得到了如下结论:当牺牲层厚度达到微米量级时,其腐蚀速率随着牺牲层厚度的增大而加快,但当其达到纳米量级时,由于固体表面存在的静电荷而产生双电层效应,这种效应对腐蚀速率的影响超过了牺牲层厚度的影响,最终使得腐蚀速率和牺牲层厚度无关. 相似文献
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牺牲层腐蚀主要受腐蚀液的扩散过程制约,由扩散方程决定.扩散系数在腐蚀过程中随温度和腐蚀液浓度变化而改变.文中对改进的腐蚀模型给出有限差分算法,由每一时刻溶液在具体位置的浓度值得出扩散系数,再由Topography模型计算前端面的腐蚀情况得到腐蚀前端行进的轮廓线.并编程对一些MEMS结构的释放过程进行仿真,最后给出实验验证. 相似文献
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用于MEMS的叠层光刻胶牺牲层技术 总被引:5,自引:0,他引:5
研究了用于制备悬空结构的叠层光刻胶牺牲层工艺.讨论了工艺中常遇到的烘胶汽泡、龟裂、起皱、刻蚀电镀种子层时产生的絮状物和悬空结构释放时的粘附等问题,并提出了相应的解决办法.借助于分层刻蚀法和逐步替换法,用叠层光刻胶作牺牲层并利用湿法释放技术,制备得到了长1400 μm、厚6 μm、宽40 μm、悬空高为10 μm的完好的悬臂梁结构. 相似文献
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S. M. Veres 《国际强度与非线性控制杂志
》2000,10(9):709-727
》2000,10(9):709-727
This work combines two well‐known approaches to control: dual control and harmonic control. The combination results in high speed of adaptation and the possibility of using feedback controllers in practical situations where traditionally feedforward controllers were preferred. The use of frequency‐selective filters results in fast adaptation without substantial increase in on‐line computing effort. The approach proposed is more suitable for adaptive cancellation of periodic output disturbances. Dual controllers are computed around each relevant frequency of the disturbance and the control input to the plant is synthesized from them. Simulations illustrate how the control scheme works. Copyright © 2000 John Wiley & Sons, Ltd. 相似文献
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Hua Ouyang Jie Bao Gustavo A. Fimbres Weihs Dianne E. Wiley 《Journal of Process Control》2013,23(8):1197-1204
This paper proposes an activation scheme for improving the mixing in the boundary layer of pressure-driven membrane systems such as reverse osmosis and ultrafiltration. Through the application of an external electric field, a flow of ions in the vicinity of the membrane surface is generated, creating an electro-osmotic flow that should reduce the extent of concentration polarization. An optimal control problem is formulated and solved to determine the waveform of the control action required to produce an electric field that can effectively increase mixing in the vicinity of the membrane surface with improved energy efficiency. This paper uses a mixing index in terms of a measure of spatial gradients of the perturbation velocities, which describes the mixing caused by both length stretching and vortices. The efficacy of the proposed control is validated by Computational Fluid Dynamics (CFD) simulations. 相似文献
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研究建立了阿特拉津的薄层层析检测方法,用水加丙酮制作硅胶G薄板,二氯甲烷作展层剂,邻联甲苯胺和碘化钾作显色剂,这种方法可以快速检测出样品中的阿特拉津;采用数码相机采集图像后运用计算机图形处理技术,可以得到高清晰层析点影像,利用PHOTOSHOP5.0有关工具测量层析点的面积,可以使测量精度大大提高,实验表明阿特拉津浓度与层析点面积之间具有较高的相关性(R2值达到0.95)。 相似文献
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Behrooz Rahmani 《International journal of systems science》2016,47(13):3180-3192
This paper is concerned with the networked control of a class of uncertain nonlinear systems. In this way, Takagi–Sugeno (T-S) fuzzy modelling is used to extend the previously proposed variable selective control (VSC) methodology to nonlinear systems. This extension is based upon the decomposition of the nonlinear system to a set of fuzzy-blended locally linearised subsystems and further application of the VSC methodology to each subsystem. To increase the applicability of the T-S approach for uncertain nonlinear networked control systems, this study considers the asynchronous premise variables in the plant and the controller, and then introduces a robust stability analysis and control synthesis. The resulting optimal switching-fuzzy controller provides a minimum guaranteed cost on an H2 performance index. Simulation studies on three nonlinear benchmark problems demonstrate the effectiveness of the proposed method. 相似文献